Had Dodi Fayed's father, Mohamed, not been immensely rich, litigious and obsessively convinced from the moment he first heard of the crash, half an hour after it happened, that it was the result of an establishment conspiracy, the whole tragedy might have been laid to rest a decade ago. He has contemptuously rejected any alternative explanations as garbage.

The Harrods boss, usually dressed in highly coloured, open-necked summer shirts - more Hawaii than high court - sat in the inquest almost every day, watching the proceedings, surrounded by senior employees and with bodyguards standing watch outside Court 73. A limousine and back-up vehicle with more staff awaited his return each day.

The inquest ostentatiously and at laborious length examined all the conspiracy theories, clearly with the intention of settling the matter once and for all, and cross-examined a cavalcade of witnesses, including the eccentric, sometimes bizarre, folk who surrounded the princess.

Diana's complementary therapist and energy healer, her personal masseuse, her acupuncturist and her former butler Paul Burrell, who has made a living out of her ever since her death, all turned up. Fayed himself gave a spectacular, day-long performance in the witness box, accusing at least 30 people of conspiring to kill the princess because she had wanted to be his daughter-in-law.

He claimed to have been one of her best friends, much closer than anyone else. The inquest heard he had courted her attention for several years, given her presents, sponsored events for her charities, allowed her privileged access to Harrods and invited her on holiday several times, though 1997 was the first time she had accepted.

When she finally stayed at the Fayed villa in St Tropez that July, taking her sons on that holiday, Dodi was summoned down from Paris by his father, abandoning his girlfriend, Kelly Fisher - who had thought they were about to be married - so that he could make himself agreeable to the princess. When Fisher, an American model, rang up to find out what was happening, Fayed Sr told her to get lost. At the inquest he called her a hooker.

On examination, the conspiracies crumbled. Several of them originated with and were solely sourced from Fayed himself and, despite all the money he had spent in a decade's investigation, had no external factual basis at all.

Was Diana pregnant? The only suggestion that she might have been came from Fayed, who said she had told him in a phone call an hour before the crash - and he had then kept the suggestion to himself until sharing it with the readers of the Daily Express three years later. There was plenty of evidence that she was not - other witnesses attested that she was on the pill and had just had her period.

Was she killed because she was about to marry a Muslim? Fayed said Dodi had told him about their plans in the same phone call but there were plenty of Diana's friends who said she had told them she needed another marriage "like a rash on the face". There was also the inconvenient fact that she had just survived unscathed an intense two-year affair with the Pakistani surgeon Hasnat Khan, a man Fayed dismissed at the inquest, saying: "You cannot marry someone like that, lives in a council flat and has no money."

Other allegations had simple explanations: was Diana's body embalmed at the Paris hospital to disguise her pregnancy? No, it was because her corpse was beginning to deteriorate in the late summer heat.

Was there a conspiracy directed by the Duke of Edinburgh and carried out on his orders by MI6? There was no evidence of this and plenty to suggest it was unlikely: would the service really have dispatched an assassin in an ageing Fiat Uno to take on a high-powered limousine? And how could it have set up such a plot in the few minutes after the plan to drive the couple back to the Fayed apartment, instead of staying at the Ritz, was formulated - particularly if the conspiracy involved both British and French security services, the French medical authorities, the police and judiciary in both countries, to say nothing of Tony Blair, Robin Cook, the then foreign secretary who was on a visit to the far east at the time, the British ambassador, the Queen's private secretary and even the princess's own solicitor?

Last night the jury's majority verdict gave Fayed a small opening by stating that the unlawful killing of the princess and Dodi had been caused not only by Henri Paul's drunken driving but also by the following vehicles. This probably meant the paparazzi, but Fayed's spokeswoman immediately suggested that those vehicles could have included unspecified possible assassins. Fayed was given the opportunity to air his allegations but it was noticeable that his legal team did not pursue most of them, including the suggestion that there were possible conspirators in the following cars. His lawyers knew, as the coroner pointed out, that there was no evidence to sustain them.

Practically the only witnesses who endorsed any parts of his claims were his employees or beneficiaries. His closest and most loyal advisers, John Macnamara, former head of security at Harrods, Michael Cole, his former director of communications, and Stuart Benson, his solicitor, were all shown to have lied on his behalf in their zeal to do Fayed's bidding and conceal inconvenient facts. In the witness box Fayed insisted the proof of what he was saying could only be found if MI6's files were opened up to investigation.

Meanwhile, as with many such conspiracy theories, the facts had to be wrestled into line to fit and, if they could not be made to do so, then they were either ignored or used to create a new, alternative, theory. Thus, Fayed's side originally contended that Paul had not been drinking when they knew within days of the crash that he had consumed two Ricards in the Ritz bar and had been missing for three hours earlier in the evening after going off duty. The missing period then came to be ascribed to his being briefed by MI6 about the forthcoming plot.

What may have surprised his legal team was the fact that the British establishment turned out in force and on the record to confront his claims and submit themselves to his lawyers' cross-examination. No fewer than 11 members of MI6, including its former head, Sir Richard Dearlove, entered the witness box.

In the end, it was the small details that were most telling: the masseuse Myriah Daniels testifying that Henri Paul had driven recklessly from the airport earlier in the day: "With all due respect he was probably a very nice man but he was shit as a driver." And the revelation of how sad and empty Diana's life was during those last months: she was at a loose end because it was the first August she was spending without her sons.

Fayed is a bereaved father, yes - but also a vengeful and controlling one surrounded by acolytes, seemingly anxious above all to deflect criticism from his own responsibility for what happened.

After Fayed's extraordinary performance in the witness box, Cole, Macnamara and Katherine Witty, his current press officer, crowded round obsequiously to congratulate him and shake his hand. The sight spoke volumes - Fayed is not a man who easily brooks contradiction. He reacted badly to being cross-examined, hurling insults at Richard Horwell QC, the Metropolitan police's counsel, for his temerity in questioning his assertions.

The inquest heard that Dodi, at the age of 42, rarely took any decisions without calling his father first. The bodyguards who reluctantly went along with the plan for the couple to be driven home by Paul were told that Fayed had okayed it and they knew better than to query his instructions. Diana had already come up with a nickname for the boss on her final holiday. The inquest heard that she said "God's calling" as she handed the mobile phone to Dodi for the umpteenth time.

The facts

The mechanical details of the most minutely examined car crash in history are simple:

· The black Mercedes S-280 driven by Henri Paul and carrying Princess Diana, her companion Dodi Fayed and his bodyguard Trevor Rees roared away from the rear entrance of the Ritz hotel in Paris at 12.20 am on Sunday August 31 1997

· The car smashed into the 13th pillar of the Alma tunnel which straddles the dual carriageway running alongside the river Seine approximately three minutes later

· Had the car not been travelling at 65mph, more than twice the speed limit, had it glanced against the pillar instead of head-on, or had it bounced off the side wall instead, the occupants might have survived. Had any of them been wearing seatbelts they might have stood a better chance, too

· Dodi and Paul were killed outright and Diana and Rees suffered major injuries

· The princess was extricated from the car, treated at the scene and transported slowly to hospital with her heartbeat erratic and her blood pressure flattening fast

· At the La Pitié-Salpêtrière hospital she was operated on by ProfAlain Pavie, president of the French college of cardiovascular surgeons, but he discovered massive internal injuries, including a tear the width of a man's fist in her superior pulmonary vein where it entered the heart. He said he had never seen a patient survive such an injury and Diana was pronounced dead inside two hours

· Prof Thomas Treasure, president of the European Association for Thoracic Surgery, queried some details of the treatment but conceded to the inquest there was a "very low likelihood" that she could have lived